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###### Environmental Protection Agency

          - [EPA-HQ-OAR-2024-0446; FRL-12501-01-OAR]

# AGENCY:

Office of Air and Radiation, Environmental Protection Agency (EPA).

# ACTION:

Notice.

# SUMMARY:

The Environmental Protection Agency (the EPA or the Agency) has approved, subject to certain conditions, the request for a “Small-scale Road Pilot Project on Private Land in Florida” submitted by Mosaic Fertilizer, LLC in March 2022, and updated by the “Revised Request for Approval of Use of Phosphogypsum in Small-scale Pilot Project”, submitted in August 2023. The Agency's review found that Mosaic's request is complete per the requirements of EPA's National Emissions Standards for Hazardous Air Pollutants under the Clean Air Act, and that the potential radiological risks from conducting the pilot project meet the regulatory requirement that the project is at least as protective of public health as maintaining the phosphogypsum in a stack. On October 9, 2024, the EPA issued a pending approval of the request and solicited public comments on the pending approval. While EPA received comments raising questions about the project, no comments were received which led EPA to change the results of its risk analyses for this proposed pilot project. This approval is only for the proposed pilot project, and EPA has placed conditions on the approval to make sure that the project remains within the scope of the application.

# DATES:

This decision is effective immediately.

# FOR FURTHER INFORMATION CONTACT:

                        Jonathan Walsh, Radiation Protection Division, Office of Radiation and Indoor Air, Mail Code 6608T, Environmental Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460; 202-343-9238;                         *Walsh.Jonathan@epa.gov.*

# SUPPLEMENTARY INFORMATION:

## I. Background

Phosphogypsum is the waste byproduct of wet acid phosphorous production. It contains elevated concentrations of the radionuclide radium, which decays to form radon gas. The EPA's regulations under the Clean Air Act at 40 CFR part 61, subpart R (hereafter “Subpart R”) require that phosphogypsum must be disposed of in engineered piles, called stacks, to limit public exposure to its radioactive components. Subpart R allows the removal of phosphogypsum from stacks for outdoor agricultural purposes and indoor research and development, subject to conditions and restrictions. Any other use of phosphogypsum requires prior approval from the EPA. The EPA may approve a request for a specific use of phosphogypsum if it determines that the proposed use is at least as protective of public health as placement of phosphogypsum in a stack. The processes for requesting such an approval are described in 40 CFR 61.206.

Mosaic Fertilizer, LLC submitted a request for a Small-scale Road Pilot Project on Private Land in Florida in March 2022, and submitted a Revised Request for Approval of Use of Phosphogypsum in Small-scale Pilot Project in August 2023. Mosaic has proposed to construct a small-scale pilot project at its New Wales facility in Polk County, Florida. Mosaic's plan is to construct four sections of test road having varying mixtures of phosphogypsum (PG) in the road base “to demonstrate the range of PG road construction designs that meet the Florida Standard Specifications for Road and Bridge construction” (Request for Approval of Additional Uses of Phosphogypsum Pursuant to 40 CFR 61.206, Small-scale Road Pilot Project on Private Land in Florida). The pilot project will be constructed in the place of an existing facility road near the phosphogypsum stack, and the study will be conducted in conjunction with researchers from the University of Florida.

                    The EPA performed a complete review of Mosaic's request, documented in “Review of the Small-scale Road Pilot Project on Private Land in Florida Submitted by Mosaic Fertilizer, LLC” (                    *www.regulations.gov,*                     Docket ID No. EPA-HQ-OAR-2024-0446). The Agency's review found that Mosaic's request is complete per the requirements of 40 CFR 61.206(b). Further, the review found that Mosaic's risk assessment is technically acceptable, and that the potential radiological risks from the proposed                           ( print page 104536)                        project meet the regulatory requirements of 40 CFR 61.206(c); that is, the project is at least as protective of public health as maintaining the phosphogypsum in a stack. Therefore, the Agency issued an approval of the small-scale pilot project per 40 CFR 61.206, subject to terms and conditions which limit the project to the scope of the application. The terms and conditions are included in the approval letter to Mosaic, which is available in the public docket and on the EPA website,                     *https://www.epa.gov/​radiation/​phosphogypsum.*                     Approval by the Agency is specific to the pilot project as described in the Mosaic request and indicates only that this project meets the approval requirements of Subpart R.                

## II. Public Comments and Responses

                    The EPA's decision to approve or deny a request for other use under 40 CFR 61.206 is not a rulemaking. In December 2005, the EPA issued a guidance document, “Applying to EPA for Approval of Other Uses of Phosphogypsum: Preparing and Submitting a Complete Petition Under 40 CFR 61.206, A Workbook” (December 2005). Although this guidance is not binding, the EPA sought public comment on this pending approval using the procedure described in Section 2.4 of the Workbook. As outlined in the Workbook, the EPA published a notice of availability of this pending approval in the                     **Federal Register**                     on October 9, 2024, and opened a 30-day comment period, which was extended in response to public requests for an additional 15 days to close on November 23, 2024. Physical copies of the Mosaic request and the EPA's technical evaluation were placed for public review in the Mulberry Public Library, 905 NE 5th Street, Mulberry, FL 33860. The EPA also placed notices of public availability in local newspapers.                

The EPA has reviewed all comments received for their relevance to the pending approval.

Many comments requested an extension of the 30-day comment period. The EPA extended the comment period in response to these requests.

The majority of comments were generally opposed to the use of phosphogypsum in public roads, and critical of the current state of phosphogypsum management; these comments were determined to be outside the scope of this action, which is specific to the small-scale pilot project as it is described in Mosaic's request. The EPA's approval applies only to the proposed pilot project and not any broader use. Any other use would require a separate application, risk assessment, and approval.

Comments related to EPA's management of phosphogypsum and its non-radiological contaminants under the Resource Conservation and Recovery Act and other statutes similarly fell outside the scope of the current decision. EPA has documented other regulatory issues in its supporting documents, but EPA's decision is only a determination of the permissibility of the project under the Clean Air Act National Emissions Standards for Hazardous Air Pollutants for Radionuclides. It does not imply any other regulatory approval or determinations of compliance. These must be obtained or made separately from this decision.

Some commenters indicated that EPA established a legal ban on the use of phosphogypsum in road construction by considering but not issuing a categorical approval in 1992. Road use is not prohibited by the regulation as amended in 1992 and is eligible to be considered as an “other use.”

Commenters were critical of many aspects of the risk assessment. Commenters questioned the EPA's overall ability to perform radiological risk assessment, use of fatal radiogenic cancers as a health endpoint, selection of dose and risk coefficients, selection of models, and selection of exposure scenarios and whether current risk data was used. Specifically, several commenters believed that greater emphasis should be placed on the consideration of a future resident at the site of the pilot project. These comments represent disagreements with decisions that EPA has made in its evaluation of potential risks associated with the proposed pilot project, rather than new information that the Agency has not previously considered. After reviewing the comments, the EPA continues to believe that the risk assessments associated with this pilot project are consistent with current radiological risk assessment methodologies and precedent, and sufficient to evaluate the project per the requirements of 40 CFR 61.206. Results from multiple modeling efforts indicate that risks due to the proposed pilot project are low. EPA believes that for this existing site, it is most appropriate to consider the potential risk to site workers and the nearest residents to the site when determining whether the pilot project is as protective as leaving the phosphogypsum in the stack. No comments raised topics which EPA did not consider in its technical evaluation or lead to a concern for human health or environmental impacts not previously considered.

                    The Agency's response to comments document is available in the public docket [1]                                          and on the EPA phosphogypsum website,[2]                                          together with electronic copies of the application, the EPA's review, and relevant background materials.                

Joseph Goffman,

Assistant Administrator, Office of Air and Radiation.

# Footnotes

1.                                                     *https://www.regulations.gov,*                         Docket ID No. EPA-HQ-OAR-2024-0446.                    
        Back to Citation      

2.                                                     *https://www.epa.gov/​radiation/​phosphogypsum#aaup.*
        Back to Citation      

[FR Doc. 2024-30508 Filed 12-20-24; 8:45 am]

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